In a thin film transistor (TFT) liquid crystal display, each of liquid crystal pixel points is driven by a pixel thin film transistor integrated behind the pixel points, and a signal on a data line in a liquid crystal panel is outputted to a pixel electrode through the pixel thin film transistor, so that the pixel electrode and a common electrode work together to make light transmittance of liquid crystal on the pixel electrode changed.
Specifically, the pixel thin film transistor is turned on when a gate scanning signal on a gate line is at a high level, so that the signal on the data line is outputted to a storage capacitor through the pixel thin film transistor, and the storage capacitor influences the pixel electrode. As a result, the pixel electrode has certain voltage and form a capacitor together with the common electrode, so as to control deflection of the liquid crystal in the liquid crystal panel and further control the light transmittance of the liquid crystal panel.
Due to space arrangement and so on, a parasitic capacitor is formed between the gate line and wiring of the storage capacitor. When a gate line scanning is ended, voltage of the gate scanning signal on the gate line is suddenly dropped from 15V to −5V. Due to the effect of the parasitic capacitor, quantity of electricity over the storage capacitor is reduced, thereby failing to provide sufficient voltage to the pixel electrode, which affects a matching effect between the pixel electrode and the common electrode and reduces the display effect of the liquid crystal display.